Motor Mounts Need Tightening

[Bobby P.]

Hello folks!

Before anyone starts freaking out, things can loosen up and that's partly do to vibration, age, time, etc. So I'm not too worried. Or should I be?

I got curious about these when I noticed one was a little crooked. I put a wrench on it and sure enough it accepted a few turns. I checked remaining 7 (2 per mount) and found that most could take a few turns.

My question is, what is on the other side of the bolt on the motor mounts on a 21017 R31? Are they lag bolted in to wooden stringers? Is there a plate and nut embedded beneath the fiberglass? Are there tolerances that they should be tightened to (it would be hard to get a torque wrench on a few). If they are over tightened, can they strip?

And finally, should this be added to a regular yearly maintenance check or am I an outlier on this one?

Thanks in advance.
Bobby

 

[TylerFromEverett]

I have a 21ec and mine loosen up too. I believe mine are lagged into stringers and I plan to drill them through and put a bearing plate/washer and a nut on the end of a bolt.

 

[BB marine]

My question is, what is on the other side of the bolt on the motor mounts on a 21017 R31? Are they lag bolted in to wooden stringers? Is there a plate and nut embedded beneath the fiberglass? Are there tolerances that they should be tightened to (it would be hard to get a torque wrench on a few). If they are over tightened, can they strip?

I am speaking for the C26 but I believe the build concept is the same throughout the inboard line. The grid has wood glassed in it where the motor mounts are to be located. The C26 has 8- 3/8" lag bolts securing it to the bed-stringer. When tightening them I think it would be hard to put a torque spec to them because they are secured in wood. Tight with discretion would be the best way I can explain tightening. You don't want to over tighten and pull the threads out of the wood.

I had one lag strip out after a year of use. Probably was stripped out when it was installed but I found it a year after owning the boat. I was surprised that the wood was used. Aluminum plating is the norm in boats built after the 90's. The wood works and that is what Fluid Motion uses. If you find one that doesn't snug up properly and the wood is still in good condition a larger lag could be used. Or drill the hole larger 5/8" and epoxy a dowel rod in the hole and drill a hole for a 3/8 lag. Good as new!

I believe it is a good idea to inspect all engine mounting hardware yearly. Not just the hold down lags but the motor mount nuts too. When checking the nuts don't just put a wrench on the top nut and check for tightness. use 2 wrenches ,back up the bottom nut and tighten the top nut. If you find movement in the nuts when tightening it may not be a bad idea to check alignment. I guess it would depend on how loose it was when found.

Before anyone starts freaking out,

It is not a big deal to find the lags loosened after a few years of operation. If inspected regularly you will find that they don't move much. It is when they are never inspected and remain loose over time problems can be experienced.

 

[daveme]

It would be nice to hear from Cutwater/Ranger on the maintenance protocol.